Extolling the region as foundational to the way of life for Alaska Natives, a sought-after destination for anglers and the source of half the world’s sockeye salmon, Mr. Biden said, “It is no place for a mine.”
The administration of President Barack Obama concluded in 2014, after a three-year scientific review, that the Pebble Mine project could have “catastrophic” effects, including a “complete loss of fish habitat due to elimination, dewatering, and fragmentation of streams, wetlands, and other aquatic resources” in some parts of Bristol Bay.
Mr. Obama’s E.P.A. issued a proposed determination under a provision of the Clean Water Act that would have acted like a veto and effectively banned mining in the area. But the agency faced several lawsuits from the Pebble Limited Partnership, and when Mr. Trump took office the determination was still not finalized.
In 2019 the Trump administration, which by then had rolled back nearly 100 environmental regulations, withdrew the Obama-era designation altogether and denounced it as “outdated” — citing lawsuits by the Pebble Mine company as one of the significant new developments.
Representatives of the Pebble Mine Partnership and its parent company, Northern Dynasty Minerals Ltd., did not immediately respond to email requests for comment.
In a statement, the E.P. A. administrator, Michael Regan, said that if the court ruled in the Biden administration’s favor, the agency would announce a schedule for resuming a process to protect the Bristol Bay from development under the Clean Water Act.
“What’s at stake is preventing pollution that would disproportionately impact Alaska Natives,” Mr. Regan said, “and protecting a sustainable future for the most productive salmon fishery in North America.”